GLOSSARY - Diseases of Fruit Crops in Australia - page 266

endophytic growth : fungal infection of internal plant tissues
without the development of symptoms.

mosaic : patchy variation of normal green colour of leaves. A
common symptom of virus infection in plants.

epidemic : a widespread and severe outbreak of an infectious disease. mottle : an irregular pattern of light and dark green areas.

fruiting body : a general term for spore-bearing structures of fungi. mummify : to dry and shrivel. A mummy is a dried and shrivelled

fruit.

fumigant : a toxic gas or volatile substance used to control pests in a
certain area. mycelium(-elia) : the mass of individual threads or hyphae that

make up the body of a fungus.

fungicide : a chemical compound that kills or inhibits fungi. A
protectant fungicide provides a protective chemical barrier over the
host surface and prevents initial infection. An eradicant fungicide
kills fungal pathogens growing within the host and so has a curative
effect. Eradicant fungicides are often absorbed and transported
within the plant.

mycoplasma : an organism similar to a bacterium but variable in
shape and lacking a rigid cell wall.

necrosis (adj. necrotic) : death of plant cells and tissues, usually
accompanied by discolouration of the affected area.

nematicide : a chemical compound that kills or inhibits nematodes.

fungus(-gi) : a class of organisms lacking chlorophyll and having
individual strands (hyphae) aggregated into mycelium. Some cause
plant diseases.

nematode : small, wormlike animals that are parasitic on plants,
other animals or free-living in soil or water.

gall : a swelling or outgrowth produced on a plant as a result of
attack by pathogens or insects.

nucellar seedling : seedling that originates from an unfertilised cell
within the nucellus and is therefore identical to the parent (e.g.
nucellar citrus seedling).

greenlife : fresh storage life of fruit.

obligate pathogen : an organism that can obtain food only from
living host plants.

gummosis or gumming : production of gum by a plant as a result of
a disease or disorder.

oomycete : a fungus-like organism that produces oospores; a water
mould.

host plant : a plant that is invaded by a pathogen and from which the
pathogen obtains nutrients.

oospore : thick-walled resting spore formed during sexual
reproduction in some fungi.

host range : the various kinds of plants attacked by a certain
pathogen.

parasite : an organism living in or on another living organism and
obtaining its food from the latter.

hypha(-ae) : one of the threads of a fungal mycelium.

imperfect state : see anamorph.

pathogen : a parasite able to cause disease in a host. The major plant
pathogens are fungi, bacteria, nematodes and viruses. infection : the establishment of a pathogen within a host plant.

inoculum : pathogen or pathogen parts capable of infecting a host
plant. Examples include fungal spores, bacterial cells and virus
particles.

pathogenicity : the ability of a pathogen to cause disease.

pathovar (pv.) : in bacteria, a subspecies or group of strains that can
infect only plants within a certain genus or species.

interveinal : lesions delimited by leaf veins.

perfect stage : see teleomorph.

latent infection : infection of a host by a pathogen without symptom
development.

pericarp : the wall of a fruit.

perithecium(-ecia) : a microscopic, globular or f lask-shaped
structure containing sexual fungal spores.

lenticel : a minute hole or pore in the fruit or stem allowing gas
exchange.

petiole : the stalk of a leaf.

lesion : a localised area of diseased tissue.

pH : symbol of a scale (0-14) used to indicate acidity or alkalinity;
0-6 indicates acidity, 7 is neutral and 8-14 indicates alkalinity.

life cycle : the successive stages in the growth and development of an
organism that occur between the appearance and reappearance of
the same stage. phloem : food-conducting tissue of a plant.

meristem : used in relation to tissue culture plants where plant tissue
is capable of undergoing mitosis and giving rise to new cells and
tissues.

phytoplasma : type of specialised bacteria, characterised by the lack
of a cell wall, that parasitise the phloem of plants.

phytosanitary practices : treatments that ensure plant material or
produce is free from pests and diseases. monoembryonic : seeds containing a single embryo.